feat: add writeJson/writeJsonSync for fs modules

fs/write_json.ts

@@ -0,0 +1,57 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import * as path from "./path/mod.ts";
+
+type Replacer = (key: string, value: any) => any;
+
+export interface WriteJsonOption {
+  spaces?: number | string;
+  replacer?: Array<number | string> | Replacer;
+}
+
+/* Writes an object to a JSON file. */
+export async function writeJson(
+  filePath: string,
+  object: any,
+  options: WriteJsonOption = {}
+): Promise<void> {
+  filePath = path.resolve(filePath);
+
+  let contentRaw: string = "";
+
+  try {
+    contentRaw = JSON.stringify(
+      object,
+      options.replacer as string[],
+      options.spaces
+    );
+  } catch (err) {
+    err.message = `${filePath}: ${err.message}`;
+    throw err;
+  }
+
+  await Deno.writeFile(filePath, new TextEncoder().encode(contentRaw));
+}
+
+/* Writes an object to a JSON file. */
+export function writeJsonSync(
+  filePath: string,
+  object: any,
+  options: WriteJsonOption = {}
+): void {
+  filePath = path.resolve(filePath);
+
+  let contentRaw: string = "";
+
+  try {
+    contentRaw = JSON.stringify(
+      object,
+      options.replacer as string[],
+      options.spaces
+    );
+  } catch (err) {
+    err.message = `${filePath}: ${err.message}`;
+    throw err;
+  }
+
+  Deno.writeFileSync(filePath, new TextEncoder().encode(contentRaw));
+}

fs/write_json_test.ts

@@ -0,0 +1,244 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+import { test } from "../testing/mod.ts";
+import {
+  assertEquals,
+  assertThrowsAsync,
+  assertThrows
+} from "../testing/asserts.ts";
+import { writeJson, writeJsonSync } from "./write_json.ts";
+import * as path from "./path/mod.ts";
+
+const testdataDir = path.resolve("fs", "testdata");
+
+test(async function writeJsonIfNotExists() {
+  const notExistsJsonFile = path.join(testdataDir, "file_not_exists.json");
+
+  await assertThrowsAsync(
+    async () => {
+      await writeJson(notExistsJsonFile, { a: "1" });
+      throw new Error("should write success");
+    },
+    Error,
+    "should write success"
+  );
+
+  const content = await Deno.readFile(notExistsJsonFile);
+
+  await Deno.remove(notExistsJsonFile);
+
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+});
+
+test(async function writeJsonIfExists() {
+  const existsJsonFile = path.join(testdataDir, "file_write_exists.json");
+
+  await Deno.writeFile(existsJsonFile, new Uint8Array());
+
+  await assertThrowsAsync(
+    async () => {
+      await writeJson(existsJsonFile, { a: "1" });
+      throw new Error("should write success");
+    },
+    Error,
+    "should write success"
+  );
+
+  const content = await Deno.readFile(existsJsonFile);
+
+  await Deno.remove(existsJsonFile);
+
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+});
+
+test(async function writeJsonIfExistsAnInvalidJson() {
+  const existsInvalidJsonFile = path.join(
+    testdataDir,
+    "file_write_invalid.json"
+  );
+
+  const invalidJsonContent = new TextEncoder().encode("[123}");
+  await Deno.writeFile(existsInvalidJsonFile, invalidJsonContent);
+
+  await assertThrowsAsync(
+    async () => {
+      await writeJson(existsInvalidJsonFile, { a: "1" });
+      throw new Error("should write success");
+    },
+    Error,
+    "should write success"
+  );
+
+  const content = await Deno.readFile(existsInvalidJsonFile);
+
+  await Deno.remove(existsInvalidJsonFile);
+
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+});
+
+test(async function writeJsonWithSpaces() {
+  const existsJsonFile = path.join(testdataDir, "file_write_spaces.json");
+
+  const invalidJsonContent = new TextEncoder().encode();
+  await Deno.writeFile(existsJsonFile, invalidJsonContent);
+
+  await assertThrowsAsync(
+    async () => {
+      await writeJson(existsJsonFile, { a: "1" }, { spaces: 2 });
+      throw new Error("should write success");
+    },
+    Error,
+    "should write success"
+  );
+
+  const content = await Deno.readFile(existsJsonFile);
+
+  await Deno.remove(existsJsonFile);
+
+  assertEquals(new TextDecoder().decode(content), `{\n  "a": "1"\n}`);
+});
+
+test(async function writeJsonWithReplacer() {
+  const existsJsonFile = path.join(testdataDir, "file_write_replacer.json");
+
+  const invalidJsonContent = new TextEncoder().encode();
+  await Deno.writeFile(existsJsonFile, invalidJsonContent);
+
+  await assertThrowsAsync(
+    async () => {
+      await writeJson(
+        existsJsonFile,
+        { a: "1", b: "2", c: "3" },
+        {
+          replacer: ["a"]
+        }
+      );
+      throw new Error("should write success");
+    },
+    Error,
+    "should write success"
+  );
+
+  const content = await Deno.readFile(existsJsonFile);
+
+  await Deno.remove(existsJsonFile);
+
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+});
+
+test(function writeJsonSyncIfNotExists() {
+  const notExistsJsonFile = path.join(testdataDir, "file_not_exists_sync.json");
+
+  assertThrows(
+    () => {
+      writeJsonSync(notExistsJsonFile, { a: "1" });
+      throw new Error("should write success");
+    },
+    Error,
+    "should write success"
+  );
+
+  const content = Deno.readFileSync(notExistsJsonFile);
+
+  Deno.removeSync(notExistsJsonFile);
+
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+});
+
+test(function writeJsonSyncIfExists() {
+  const existsJsonFile = path.join(testdataDir, "file_write_exists_sync.json");
+
+  Deno.writeFileSync(existsJsonFile, new Uint8Array());
+
+  assertThrows(
+    () => {
+      writeJsonSync(existsJsonFile, { a: "1" });
+      throw new Error("should write success");
+    },
+    Error,
+    "should write success"
+  );
+
+  const content = Deno.readFileSync(existsJsonFile);
+
+  Deno.removeSync(existsJsonFile);
+
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+});
+
+test(function writeJsonSyncIfExistsAnInvalidJson() {
+  const existsInvalidJsonFile = path.join(
+    testdataDir,
+    "file_write_invalid_sync.json"
+  );
+
+  const invalidJsonContent = new TextEncoder().encode("[123}");
+  Deno.writeFileSync(existsInvalidJsonFile, invalidJsonContent);
+
+  assertThrows(
+    () => {
+      writeJsonSync(existsInvalidJsonFile, { a: "1" });
+      throw new Error("should write success");
+    },
+    Error,
+    "should write success"
+  );
+
+  const content = Deno.readFileSync(existsInvalidJsonFile);
+
+  Deno.removeSync(existsInvalidJsonFile);
+
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+});
+
+test(function writeJsonWithSpaces() {
+  const existsJsonFile = path.join(testdataDir, "file_write_spaces_sync.json");
+
+  const invalidJsonContent = new TextEncoder().encode();
+  Deno.writeFileSync(existsJsonFile, invalidJsonContent);
+
+  assertThrows(
+    () => {
+      writeJsonSync(existsJsonFile, { a: "1" }, { spaces: 2 });
+      throw new Error("should write success");
+    },
+    Error,
+    "should write success"
+  );
+
+  const content = Deno.readFileSync(existsJsonFile);
+
+  Deno.removeSync(existsJsonFile);
+
+  assertEquals(new TextDecoder().decode(content), `{\n  "a": "1"\n}`);
+});
+
+test(function writeJsonWithReplacer() {
+  const existsJsonFile = path.join(
+    testdataDir,
+    "file_write_replacer_sync.json"
+  );
+
+  const invalidJsonContent = new TextEncoder().encode();
+  Deno.writeFileSync(existsJsonFile, invalidJsonContent);
+
+  assertThrows(
+    () => {
+      writeJsonSync(
+        existsJsonFile,
+        { a: "1", b: "2", c: "3" },
+        {
+          replacer: ["a"]
+        }
+      );
+      throw new Error("should write success");
+    },
+    Error,
+    "should write success"
+  );
+
+  const content = Deno.readFileSync(existsJsonFile);
+
+  Deno.removeSync(existsJsonFile);
+
+  assertEquals(new TextDecoder().decode(content), `{"a":"1"}`);
+});

test.ts

@@ -19,6 +19,7 @@ import "./fs/ensure_dir_test.ts";
 import "./fs/ensure_file_test.ts";
 import "./fs/move_test.ts";
 import "./fs/read_json_test.ts";
+import "./fs/write_json_test.ts";
 import "./io/test.ts";
 import "./http/server_test.ts";
 import "./http/file_server_test.ts";